The present invention relates generally to an electrophotographic copying machine of a type having a multi-copy mode in which the machine performs its copying operation with copying papers automatically fed one at a time from a paper supply unit and a manual feed mode in which the machine performs its copying operation with copying papers fed manually one at a time.
In general, a present-day electrophotographic copying machine is so designed that, if the operator of the machine preset to a counter the number of copies desired to be made, the copying operation can be repeated in succession a number of cycles equal to the number of copies desired to be made. At this time, the contents of the counter are displayed by a digit display unit utilizing either light emitting diodes or liquid-crystal display elements to show the number of copies being made. The method for displaying or counting the copies being made is generally based on a count-down system such as disclosed in the U.S. Pat. No. 4,105,914, or a count-up system. Some copying machines employ either a display unit capable of showing a preset number of copies to be made or a counter for counting the number of copies being made in combination with a count-down counter or a count-up counter, examples of which are disclosed in the U.S. Pat. No. 4,202,622 and the Japanese Laid-open Patent Publications No. 53-125839 and No. 53-127729 both laid open to public inspection in 1978.
For enabling an images to be copied on each side of a copying paper and/or enabling a special paper to be utilizable in reproduction of an image, some conventional copying machines have a manual paper feed unit provided separately of an automatic paper feed unit so that the machine can be set to operate with the copying papers manually fed from the manual paper feed unit at a time and with the copying papers automatically fed from the automatic paper feed unit at the other time.
One form of the manual paper feed unit comprises a manual feed table supported by a machine housing for pivotal movement between closed and opened position such that, when the table is held in the opened position, the machine can automatically set to operate under a sequence control mode with the copying paper manually fed through the table and, at the same time, the machine can be held in condition ready to receive the copying papers manually fed one at a time. An example of this is disclosed in the U.S. Pat. No. 4,204,668.
Another form of the manual feed unit comprises a removable feed table having a signal generating element such as a magnet or an actuating projection, which removable feed table can be removably inserted or loaded in a paper supply unit so designed as to accommodate a paper cassette containing a stack of copying papers. In this construction, when the removable feed table is loaded in the machine in place of the paper cassette, the signal generating element carried thereby actuates a switch element to set the machine in a condition ready to operate with copying papers manually fed through the removable feed table.
In any event, any one of the conventional copying machine is so designed that, when the automatic paper feed unit is in operation a counter counts the number of copies being made, and the display unit displays the number of copies actually made or left unfinished on the basis of a result of the counting operation of the counter. No conventional copying machine even though it has a capability of accommodating copying papers manually supplied one at a time in addition to the capability of accommodating the paper cassette containing a stack of copying papers, has not yet been provided with means for displaying the number of copies made on the manually supplied copying papers, and accordingly, the operator of the machine has long been forced to encounter with such an inconvenience as to count the number of copies by memorizing it. This is particularly true where a number of copies each having its opposite faces bearing respective images are made in succession using either ordinary copying papers or special papers.
Accordingly, the applicant of the present invention previously proposed an arrangement in which the preset counter acts also as a counter device for counting the number of copies made on the manually supplied copying papers in the Japanese Patent Application No. 55-40982. However, the above described arrangement has an inherent disadvantage that it cannot be applied to a copying machine of a type in which copying papers can be fed manually at any time. Namely, in the copying machine of the type which does not require to be switched over to the manual feed mode so as to be operated with copying papers being manually fed, the preset counter cannot be switched over to the counter device for counting the manually fed copying papers and thus, the preset counter cannot act also as the counter device for counting the manually fed copying papers.